1. Field of the Invention
The subject invention generally relates to locating pins for inserting into a work piece to position and hold the work piece. More specifically, the subject invention relates to a locating pin having an extendable finger or fingers for holding the work piece in place and for retracting into the locating pin to allow the work piece to be removed from the locating pin.
2. Description of the Prior Art
Various locating assemblies are known to those skilled in the art which employ a locating pin to precisely position a work piece. These locating assemblies include an extendable clamping arm, or finger, to hold the work piece in place, as illustrated in U.S. Pat. No. 6,378,855 to Sawdon et al.
The '855 patent to Sawdon et al discloses a locating assembly having a housing and a locating pin. A steel shaft inside the housing has a pair of hooks. The pair of hooks are extendable from the locating pin through a pair of vertical slots. A first dowel passes through a slot of the steel shaft and is attached to the housing. A second dowel runs through a bottom of the steel shaft. A pneumatic piston has a slot for receiving the second dowel and for controlling the steel shaft as the pneumatic piston is moved.
A clamping cycle begins when the pneumatic piston is moved in a horizontal direction, guiding the second dowel through the slot in the pneumatic piston and moving the steel shaft. As the steel shaft moves, the slot in the steel shaft moves along the first dowel, thus guiding the shaft. The first and second slots are shaped such that as the pneumatic piston is moved, the steel shaft is forced out of the locating pin and pulled in a downward vertical direction to hold the work piece with the hooks.
The locating assembly disclosed in the '855 patent, among other similar locating assemblies of the prior art, is expensive and difficult to maintain. For instance, the hook disclosed in the '855 patent, while being subjected to forces in many directions, is prone to failure due to fatigue. Furthermore, the hooks are limited to a single path of motion, depending on a shape of the first and second slots, and thus cannot be adjusted. This may result in too great of a clamping force being applied to the work piece, causing denting, or conversely, too little clamping force, allowing the work piece to move while being worked on. When using multiple clamping devices, clamping forces at each device may vary, resulting in clamping that is not uniform, damage to the work piece, or movement of the work piece while being worked on. The locating assemblies of the prior art also require extra time to both extend out of the locating pin and then clamp down on the work piece. The extra time cuts down on production speeds and reduces efficiency.
Thus, it would be advantageous to provide a locating assembly that may be adjusted to provide an ideal clamping force on work pieces of various thickness. It would also be advantageous to provide a locating assembly having extendable fingers that are less susceptible to failure to eliminate aspects of existing locating assemblies that require extensive maintenance, thus streamlining manufacturing operations. It would also be advantageous to provide a locating assembly capable of working faster, more efficiently, more precisely, and more uniformly by extending and retracting at least one finger from the locating pin simultaneous with a downward movement of the locating pin. It would also be advantageous for these extendable fingers to have minimal gaps around them so that no foreign materials or contamination enters and destroys the internal mechanism.